I want to solder a 10-pin male IDC header to the Linksys JP1 header on my WRT54G v2. I'm a little "spooked" because I can't insert the IDC header into the holes in JP1. The holes feel hard and look like they are silvery in color -- perhaps they are solder filled? I've never encountered these in my limited soldering experience. How do I solder the IDC header to JP1? How do I get all the header pins to go through the 10 holes of JP1 and then sit there nicely so I can solder them? Many thanks for your help!